text: Biogas is composed mainly of methane () and carbon dioxide (), with some traces of hydrogen sulphide, oxygen, nitrogen, and hydrogen. Macroalgae has high methane production rate compared to plant biomass. Biogas production from macroalgae is more technically viable compared to other fuels, but it is not economically viable due to the high cost of macroalgae feedstock. Carbohydrate and protein in microalgae can be converted into biogas through anaerobic digestion, which includes hydrolysis, fermentation, and methanogenesis steps. The conversion of algal biomass into methane can potentially recover as much energy as it obtains, but it is more profitable when the algal lipid content is lower than 40%. Biogas production from microalgae is relatively low because of the high ratio of protein in microalgae, but microalgae can be co-digested with high C/N ratio products such as wastepaper. Another method to produce biogas is through gasification, where hydrocarbon is converted to syngas through a partial oxidation reaction at high temperature (typically 800 °C to 1000 °C). Gasification is usually performed with catalysts. Uncatalyzed gasification requires temperature to be about 1300 °C. Syngas can be burnt directly to produce energy or used a fuel in turbine engines. It can also be used as feedstock for other chemical productions.